1. Field of the Invention
The present invention relates to detergent compositions suitable for topical application for cleansing the human body, such as the skin and hair. In particular, it relates to isotropic compositions containing particulate optical modifier(s) that changes the appearance of the skin after wash off.
2. Background of the Art
The visual appearance of skin is normally changed by using personal care compositions that are left on the skin. However, it would be useful if the visual appearance of skin could also be changed by using cleansing compositions that are washed off the skin. Such products would be beneficial to consumers who are looking for multiple functionalities in their cleansing products, such as cleansers that simultaneously cleanse and moisturize. In this case, products that cleanse the skin will also make it shine, sparkle, or glow by leaving behind solid particles that affect the interaction of light with the skin. These cleansers would save consumers the time required to apply a leave-on product that will change the visual appearance of the skin, and will also give them the benefit of appearing more attractive. Optionally, these cleansers could also contain moisturizers and emollients to condition the skin and one or more active agents which can be used to deliver a benefit to the skin and which generally are not used to confer a conditioning benefit.
Prior art skin cleansers modify the way the skin feels after the shower by depositing materials such as oils or polymers. Such materials deposit on the skin by various mechanisms, including attraction of cationic materials to the anionic surface of the skin. However, materials that change the feel of the skin do not generally change the look of the skin.
Surprisingly it has been discovered that by incorporating certain solid particles and a specific cationic polymer in a cleanser formulation, the visual appearance of the skin can be modified after wash off without the need for a complex delivery system employing specific oil droplets.
U.S. Pat. No. 6,395,691 issued to Tsaur on May 28, 2002 directed to a personal wash liquid formulation, discloses the use of a particle-in-oil dispersion to deliver solid particles to the skin that are effected by adjusting the size of the oil droplet and the size ratio between the oil droplet and the particles, and employs large droplets of petrolatum or thickened oil to deposit particles. The composition of Tsaur contains 2 to 20% by wt. of such a particle-in-oil dispersion.
In a co-pending U.S. patent application Ser. No. 10/443,396 filed on May 22, 2003 by Zhang et al. relating to the deposition of particles from a cleanser, the particles being deposited are small (under 20 microns) and the formulations disclosed rely on structured oil to deposit the particles. In another co-pending U.S. patent application Ser. No. 10/241,401 filed on Sep. 11, 2002 by Zhang et al. relating to the deposition of particles from a cleanser, the particles being deposited have a specified geometry and refractive index and the formulations disclosed rely on a particle-in-oil dispersion to deposit the particles. The present invention differs from Tsaur and Zhang et al. in that it does not employ either a particle-in-oil dispersion nor a structured oil to deposit particles as it's predominate deposition mechanism.
Cosmetic formulations that are left on the skin and contain solid particles to modify the skin appearance are well known. For example, many currently available lotions contain mica coated with titanium dioxide or iron oxide that make the skin sparkle. Wash-off cleanser formulations that contain solid particles to modify the appearance of the cleanser itself are also well known. For example, many currently available body wash products contain mica coated with titanium dioxide to give the product a shimmering appearance. In addition, cleanser formulations may contain solid particles to give the formulation abrasive characteristics and to exfoliate the skin. Many products that are marketed as exfoliating cleansers contain particles such as polyethylene or various fruit seeds to scrub the skin.
US Publication no. 2003/0134759 A1 published on Jul. 17, 2003 to Geary et al. describes a formulation that contains surfactant, water insoluble solid particles, a synthetic cationic polymer, and a phase separation initiator and which contains from about 0.025% to 5% by weight of an organic, non crosslinked, cationic homopolymer or copolymer having a cationic charge density of from about 2 meq/gm to about 10 meq/gm and an average molecular weight of from about 1,000 to about 5,000,000. The solid particles are deposited when the phase separation initiator causes the polymer to form a liquid crystal phase. Unlike Geary, the cleansing composition of the present invention does not contain a liquid crystal phase.